My decent(ish) finds in Feb 2012: 1 Yellow-browed Warbler Carnon Downs 04/02, 1 Water Pipit Carnon Downs 04/02, 1 Smew Loe Pool 01/02

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Saturday, 31 October 2009

Green(ish) Warbler - part 3

Managed to get down before first light and nail a recording of the bird as it emerged from roost calling. Downloadable from here. Recorded with a Seinheisser ME66 onto an Olympus LS-10 Linear PCM digital recorder as a wav file (thanks to Thor Veen for the loan of the equipment - Dave when am I getting mine back!).  Excuse the rather poor quality and sounds of Stuart Piner getting the assembled masses onto the bird. It was quite distant with a lot of background noise. A mp3 version kindly cleaned by Hugh Harrop using a high-pass filter is available from here. In my opinion very similar to this call of a normal Greenish on the Xeno-Canto website by Wouter Halfwerk in Kiat Ngong wetland.

A recording of a Green Warbler by Stuart Fisher in Kumarakom, India is available here and one of a Two-barred Greenish by James Eaton at Mondulkiri in Cambodia here. Note the lack of House Sparrow like "chirrup" quality to the Greenish Warbler, present in both Two-barred and Green. The Church Cove bird also lacks this.

The top sonogram was kindly created by Hugh Harrop is a high temporal resolution version of two of the clearer calls. The bottom version, created by Neil Hagley is a longer version of the recording. Both are a near-perfect match of the Greenish Warbler sonograms published in the 2001 Dutch birding article by van der Vliet et al, available here (if you subscribe to RBA - you can also get it with the 7 day free trial), Green has a W-shaped sonogram and Two-barred even more peaks and troughs. There are a whole bunch of useful songs and sonograms here.

Incidentally - there are some more photos of the bird here. The third one down initially struck me as particularly interesting as it does suggest that the bird had a more typical Green Warbler wing formula - i.e. P3 and P4 are the longest and P2 is between P6 and P7 in length. In Greenish P4 and P5 are generally (although not always) the longest and in only 14% of females and 9% of males is P2=P6-7 (see Dutch Birding article here). However, there are some more photos in the UK400Club blog here. On this photo, the wing formula is suggestive of Greenish - i.e. P4 & 5 look the longest and p2=P7-8. This demonstrates the hazard of determing wing formulae from photographs.

Thursday, 29 October 2009

Green(ish) Warbler - part 2

I got down to Church Cove a bit after first light and the bird had already been found. It had been calling continually, but wasn’t when I arrived. Unfortunately those present first thing, weren’t particularly familiar with the call and were unable to say which species it was. I played my iPod (which I’d also been playing in the car on the way down) to a few present, and most people seemed to think it was closer to Greenish, but few were willing to commit with 100% certainty. I heard it call once in flight, to me it sounded more like Greenish, but hard to tell on one call. Those who’d seen it initially suggested that the bird had quite a distinctive yellow wash to the underparts, supporting Green. For the next few hours, it showed briefly at intervals up in the canopy, generally in quite poor light as it became very misty. I saw it quite well on a number of occasions –  in all of the views I got, it looked very lacking in yellow, the supercilium had a hint of very pale yellow (but no more than this one) and the wing-bar (strong) looked creamy. Had I seen it without prior knowledge of it being a possible Green, I would quite happily have passed it off as being a bog-standard Greenish (obviously after eliminating Arctic). The only slight oddity was that it looked a bit drab, or dingy below. Others commented on seeing a yellow wash to the bird under certain lighting conditions, but I just didn’t get this at any time.  However, the tone of the bird did seem to vary quite a lot dependant on how silhouetted it was. During the morning, I also heard it call again once, and again in my opinion it sounded a bit odd, but more like Greenish. We also gave it a bit of Rare Eastern Vagrants on the iPod and seemed to get a bit of a behavioural response from Greenish and not Green, but not really enough of one to say anything important about this. I voiced in my opinions on the appearance and call at the time and didn’t really receive any resistance, but was very mindful of the fact that others had seen it in better light before I got there. I did phone RBA though, stressing that I wasn’t 100% sure, but that I thought it was a bog-standard Greenish and as such, a drive across the country probably wouldn’t be worth it. I should also add that my field experience of this group is very limited – I’ve found 3 Greenish Warblers in Norfolk in the last three years (which I obviously grilled closely) and have seen two others, but have never seen Green or Two-barred and have never seen Greenish abroad.

The bird then disappeared for several hours. Most people stayed on, as all of us were unsatisfied with the lighting conditions under which we had seen the bird and only one or two voiced opinions on the call. Fortunately it was relocated about mid-afternoon after the mist had cleared and showed well (or as well as a phyllosc can) for about 20 minutes, and was seen by the 30 or so  birders present. It then became quite obvious the bird really didn’t have distinctive yellow wash to the underparts and the throat etc. The supercilium was indeed washed with a very pale lemon-yellow, but in my opinion, pretty standard for Greenish Warbler. The wing-bar was strong, but creamy rather than yellow-tinged and the throat and face lacked a distinctive yellow wash to suggest Green (at most only a hint of pale yellow). Other observers, including one person who got it through a telescope noted that the supercilium did not meet in front of the eye, which is a pro-, but my no means definitive Green rather than Greenish feature. I missed this, but I completely believe that this was the case.

In short, I appreciate that they can be very tricky to identify at times, but to me the real question is, was there anything to suggest it was a Green rather than Greenish? I appreciate that both would be rare in Cornwall, but personally I just didn’t see anything at any point that made me think anything other than Greenish. I would welcome comments from anybody else who saw it today, particularly if you heard it (I missed it both times when it was calling continually). Also, if anybody with field experience from Asia has any thoughts I would be interested to hear them.

Wednesday, 28 October 2009

Green(ish) Warbler

A bit of a frustrating day today. I was down at Church Cove fairly early morning, but didn’t give it a very thorough search as I bumped into another birder who had just given the area a blast without seeing much. I did encounter a flock of phylloscs upon arrival and glimpsed one which appeared to have a shortish tail, but my bins were steamed-up, so I went back to the car to get a cloth to clean them and could only relocate a firecrest, which I assumed it to be. After a blast of the Housel drinking pools and the Youth Hostel gardens (nowt bar a Black Redstart) I headed home. Shortly after getting there, I got a text from Tony – “Greenish reported church cove by end house mariners cottage”. Ouch! Realising the date (and hence the possibilities) – I decided to head straight back. I arrived at about the same time as Andy and a few visiting birders. No sign for a couple of hours, but news trickled through that it might be a Green Warbler. Double ouch! As the bird hadn’t been seen I was confused as to how the bird had changed identity, so phoned Stuart Piner at RBA to find out the story. Found by a visiting birder from Cambridge – one Mr Poyser. I relocated the bird while actually on the phone to Stu (who says blokes can’t multi-task!), but decided on single-tasking and hung-up before getting the full story. Myself and about five other birders managed reasonable views, but in very poor light. I gave it a blast of Rare Eastern Vagrants on my iPod, but it didn’t respond to either, nor did it call. To me it seemed very fresh – clean white underneath rather than yellow, but with a bit of yellow in the supercilium. Based on my views, I’d lean towards Greenish rather than Green, but the light was appalling and I'm sure the original finders would have seen it much better. No hint of a second wing-bar that I could make out. Certainly one of the "Green(ish)" super-species rather than a wing-barred Willow though. It was favouring the trees around the pool near the carpark rather than the bushes down by Mariners cottage and crossing over to the graveyard on occasion. I’ll be down first light tomorrow to try and get better views. A very late date for a Greenish!

Monday, 19 October 2009

Expect the unexpected

Thursday morning saw Thor Veen and yours truly down at Church Cove for yet another pre-work blast of the bushes. First light, mid-October, a light south-easterly, overcast conditions and a fair few grounded migrants. Just right for something from the east: Red-throated Pipit, Red-flanked Bluetail? The possibilities were endless. It was therefore with an air of expectation that I checked the trees around the pond at Church Cove. What would it be? Taiga Flycatcher? Eastern Bonelli’s Warbler? Redstart or Yellow-browed more likely. Some interesting passerine if anything at all. What I certainly didn’t expect, is what I saw: a roosting Cattle Egret! WTF? Unfortunately it saw me at around the same time as I saw it and it decided to depart. Even more unfortunately, Thor “was trying his luck in the graveyard” (his words, not mine), and missed it, despite my attempts to call him as it flew over him. It just goes to show though: you never can predict what’s about.

PS. Discovered shortly afterwards that it may have been in the area for several days, but in true Lizard fashion was suppressed. I decided to follow this example, only informing a few local birders. If roosting in the area, it would have been horribly prone to disturbance (as I inadvertently discovered myself). I’ve checked several times and I don’t think it’s roosting there anymore. Bound to be around somewhere though....

Sunday, 11 October 2009

Humble beginnings?

I was curious to note that Kate Humble has been elected as the new president of the RSPB (see here). Needless to say, a position of gravitas and levity. But what's that I spy? That couldn't possibly be the new president cavorting naked in front of the camera could it?

Friday, 9 October 2009

More on Brown Shrikes

Having done a fair bit of reading over the last few days and having received many helpful comments from other birders, I now feel a bit better qualified to comment on the identification of this shrike. In short, I think it is a Brown Shrike, intend to submit a description to the BBRC, but suspect that we may not quite have enough to get it through. The only sure fire way to clinch these buggers is on wing-formula (see right - click on image to see it properly ). Actually, the Lizard bird represents a bit of a test case as to whether these birds can be accepted without in-hand measurements or clear photographs of the primaries (devine revenge for my post about field notes?). Typically Brown has 4-5 exposed primaries, Izzy 6-7 and Red-backed 7-8. Note - all these figures include P2, which isn't always visable. Overall, this generally leads to an impression of shorter primary projection in Brown Shrikes (a feature of our bird), but note how this is partly due to the wing formula. Also compare here and here to see why I think estimating primary projection in the field can be subjective (both photos are of the same Red-backed Shrike).

First-off, a bit of an overview of taxonomy of this and the confusion taxa. Basically there are four or maybe three races of Brown Shrike (the nominate (
cristatus), lucionensis, superciliosus and confuses.
The last one isn’t diagnosable and may represent an integrade between cristatus and lucionensis. Only cristatis is likely to get here (the others are mega far-east) and has breeding and wintering grounds overlapping with e.g. Radde's Warbler. Many of the typical Brown Shrike features (e.g. long tail) are accentuated in the eastern races, so those of you familar with Brown Shrikes from the far-east may not appreciate the extent to which they can be quite similar to other shrike species. There are four races of Isabelline Shrike. It all becomes bit of a 'mare naming them, as the old type specimen was attributed to a different race, so that race became the nominate (see Pearson 2000 Bull. B.O.C - also here). However, it’s also been argued that Pearson’s changes are not valid as the type was actually a hybrid (Panov 2009, Sandgrouse), so it might change again. I’ll stick to Pearson, in which case we have isabellinus (Daurian Shrike), phoenicuroides (Turkestan Shrike) and aranarius and tsadamensis. Only isabellinus and phoenicuroides are serious vagrancy cabdidates as the others are short-distance migrants from the far-east. Red-backed shrikes comprise three taxa: the nominate collurio (Europe), pallidifrons (Siberia) and kobylini (Caucasus and Crimea). The fourth: juxtus was the British type that’s now extinct. Anyway there's some good photos of eastern Shrikes here even though most represent races unlikely to get here.

Second-off – why is almost certainly not a red-backed shrike? Firstly, very few 1st winters or females have very dark, almost black ear coverts (see here for a typical one). However, red-backed shrikes, especially the eastern ones are a very variable and some females can look very like males. Males have black ear-coverts, and male-type females do too. It's conceivable that the odd female or juvenile does get quite dark, like the Scillies bird last year, which had a typical Red-backed Shrike wing-formula (see here - you'll need to login to surfbirds though - browner than ours though). More importantly - 1st year shrikes of both Brown and Red-backed have distinct pale fringes to the tertials (and greater coverts) and adults (second years?) only rarely do. This feature was noted in the field by several observers, suggesting our bird was a 1st winter. Other features in support of it being a first-year was the barring on the upper-tail coverts observed in the field. Adults also generally have darker-based bills and dark lores. 1st winter Red-backed Shrikes always have distinct heavy streaking on the back, lacking on Brown. The photos show only feint streaking and from field observations I'm confident that heavy streaking was lacking. Another feature in favour of Brown, was the observed clear-cut and bolder fringing on the coverts (see here - again login to surfbirds). The bird on top is a Brown, the lower Red-backed). Other supporting features in favour of Brown are the general tone of the bird and the lack of obvious grey nape.

This leaves isabellinus (Daurian Shrike) or phoenicuroides(Turkestan Shrike). I think the general tones of the bird rule out Daurian Shrike. They never really look anything like our bird. I think the serious sticking point is whether the bird was an usually brown Turkestan Shrike lacking the typical rusty tail, the latter being the very reliable feature, alhtough often this can be a bit subtle - see here for an example). In the field, I saw no evidence of an obvious rusty tail. The photos suggest the uppertail coverts and rump are slightly rusty and do show some contrast with the mantle, but the lower tail appears much browner. This is a pattern quite normal in brown shrikes, and not evident in photos of Isabelline Shrikes I've seen. Whether it's entirely unprecedented, I'm not sure of though. Two other features strongly suggestive of Brown over Turkestan are the very dark-brown ear coverts and very obvious pale supercilium. Again, I'm yet to see photos of a bird of either race with such a distinct supercilium, but welcome comments to the contrary.

Anybody who fancies a bit of further reading - I thoroughly recommend Tim Worfolk's article in Dutch Birding (2000, 22:323-362).

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